In well designed chemical processing plants, materials selection is based on a number of factors such as service history, field in-plant corrosion tests, pilot plant and laboratory corrosion tests. But, over time, laboratory tests have proven to be the most reliable and simple mean to generate information for the selection of process materials. Many of these tests are routinely performed to provide information on: (reference)
Fundamental corrosion evaluation;
Corrosion prevention and control;
Acceptance of quality assurance;
Environmental issues involving corrosion
New alloy/non-metallic or product process development.
The Corrosion Tests and Standards Handbook subdivides laboratory corrosion tests into four categories:
In order to understand how environmental conditions can be accelerated, one has to first recognize the complexity of this factor. An important point for the description of the environment is the distinction between nominal and local (or near surface) environments. Generally, components are designed to resist nominal environments specified by the applications and service conditions. The planning of testing programs is based on these specifications. Modern testing practices reflect this complexity by building variations in the tests or by focusing on the worst case aspect of a situation.